Chemical dispensers are used to inject chemicals into gas well. Some have rotating cartridges to store the chemicals. In U.S. Pat. No. 4,785,880 (Ashton), a moving valve member that also opens and closes the valves engages a sloped cam surface at the top of its stroke to cause the cartridge to rotate. The cam surface is connected to a spring and ratchet surface, such that it returns to its original position after rotating the cartridge. In U.S. Pat. No. 6,269,875 (Harrison, III et al.), the cartridge is rotated by either a motor driving a gear profile on the outside of the cartridge, or a ratchet that is driven by the piston that opens and closes the valves. In U.S. Pat. No. 6,056,058 (Gonzalez), a piston pushes an arm which causes a ratchet system to advance.